Low frequency studies of the Galactic centre with GMRT

Abstract

We have observed the GC region at 255 and 154 MHz with the GMRT. From the 255 MHz map we detect 28 compact sources, and an anti-correlation of their deconvolved sizes with angular distance from the GC is observed. This is the first direct indication of scatter broadening for a statistically large sample of extragalactic sources in the region and we discuss its implications in determining the properties of the screen. Our multifrequency observations at 255 and 154 MHz in tandem with previous observations of the GC shows that the 7' halo in Sgr A complex is a non-thermal source rather than a mixture of thermal and non-thermal electrons as was proposed before.